Separating machine and process



Nov. 24, 1936. K. DAVIS 2,062,211

SEPARATING MACHINE AND PROCESS Filed Jan. 4, 1954 4 Sheets-Sheet 1 Wane/ac Nov. 24, 1936. K. DAVIS SEPARATING mcunm AND PROCESS Filed Jan. 4, 1934 4 Sheets-Sheet 2 l Mm A N Nov. 24, 1936. K. DAVIS SEPARATING MACHINE AND PROCESS 4 Sheets-Sheet 3 Filed Jan. 4, 1934 -Nov. 24, 1936. K DAV|5 SEPARATING MACHINE AND PROCESS Filed Jan. 4, 1934 4 Sheets-SheetA TIE-.5:

5 llln (11101111 III! Patented Nov. 24, 1936 PATENT OFFICE SEPARA'IING MACHINE AND PROCESS Kenneth Davis, Cresson, Pa.,' assignor of one-half to Samuel Whitmore Blalrslee, Pottsvllle, Pa.

Applicationianuary 4, 1934, Serial No. 705,299

' 27 Claims. (Cl. 209-466) The invention relates to dry separation of intermixed divided materials of different specific gravities, and the term divided will be understood as referring to materials in relatively small parts, as contrasted with materials in comparatively large masses or chunks, and the term will apply to broken, pulverulent or otherwise divided materials which can be separated by the present machine and process. Examples of intermixed divided materials are coal and the rock and other waste mixed therewith as it comes from the mine, and the primary intent of the present invention is to provide for effectively, expeditiously and inexpensively separating these materials. In so doing, the intermixed materials are first pre-sized instead of endeavoring to stratify numerous sizes simultaneously, for it has been found that only in this way, can the best results be attained, particularly with the finer materials, say one-eighth inch or smaller. The present invention will effectively separate these relatively fine materials but may also be used for separating sizes up to, say two and one-half inches. It is possible also that other sizes could be eifectively handled and I am not therefore to be considered as restricting myself to separating sizes ranging only from two and a half inches down to say minus one-eighth inch.

In certain separators with which I am familiar, a bed of pre-sized intermixed coal and refuse passes over a perforated plate, and air under pressure is upwardly discharged through the plate perforations to float the relatively light coal to the top of the bed, but in such machines, it is impossible to keep the relatively heavy refuse at the bottom of the bed, due to upward air currents, and this diificultyis particularly marked when attempting to clean the smaller sizes, requiring such accurate regulation of air pressure as to be practically impossible of attainment. Such machines therefore discharge entirely too much good coal with waste and they must be encumbered with means for returning or recirculating a so-callcd middling product containing good coal and refuse, to the table for re-treatrnent. Passage cf 'the materials over successive separating units can, of course, be effected but as the attempt is made to float the coal, the air requirements are very expensive. Then too, expensive conveying equipment must be used, adding greatly to initial cost, operating cost and maintenance, and if it is desired to reclaim practically all of the good coal, it is necessary to pass the waste product over a unit known as the re-treatment unit,

all this adds to degradation.

My machine operates with a comparatively thin bed, approximately 2" but I get a comparatively large capacity due to a plurality of discharge outlets which permits material to travel. along the unit at a greater velocity, also the lighter materials have a very short distance to travel to the discharge.

In machines somewhat similar to those above discussed, it is attempted to separate the coal and waste without pre-sizing, but long'experience has shown this to be unsatisfactory when handling the fines. These machines have a relatively large capacity but must operate with a very thick bed of materials, six or eight inches deep,

placing excessive strains and wear on table, supporting means and operating means. Moreover, such machines must return a middling product for re-treatment and they require a special retreatment table.

It is to overcome such drawbacks as those above enumerated that I have produced the present invention which is disclosed in the accompanying drawings in a preferred embodiment.

Fig. 1 of the drawings is a side elevation partly in section showing a separator constructed in accordance with the invention.

Fig. 2 is a top plan view with parts removed and broken away.

Fig. 3 is an enlarged fragmentary top plan view illustrating one of the separating pans and the. associated means for agitating the advancing bed of material and directing jets of air other than upward or downward into said bed.

Fig.4 is a longitudinal sectional view on line 4-4 of Fig. 3. V

Fig. 5 is a vertical transverse sectional view on line 55 of Figs. 1 and 3.

Fig. 6 is a fragmentary transverse sectional view out further-up on the separating pan, on line 66 of Fig. 3.

Fig. 7 is a view similar to a portion of Fig. 6, but showing the hollow air-discharging agitators in section.

Figs. 8 and 9 are horizontal sectional views through two of the hollow air-discharging agitators.

Fig. 10 is a fragmentary side elevation illustrating the movements or impulses imparted to the separating pans.

Fig. 11 is a diagrammatic view showing th means for periodically operating the discharge I machine, all of the separating pans will operate the invention as claimed, numerous variations may be made.

A horizontal frame I2 is provided to carry one or more separating pans, and in the present disclosure, three of such pens are mounted in inclined positions upon said frame, in overlapping relation. The coal and waste are continuously fed through suitable means F, into the lower end of the first pan I3 which performs one separating operation, the coal with only a small quantity of waste being discharged through outlets I4 into the pan I3, while the relatively heavy waste is discharged at the upper endof pan I3, through troughs or the like I6. The pan I3 performs a second separating operation, discharges the coal at I4- into the lower end of the pan I 3 and discharges the relatively heavy waste at I5. A thirdseparation is performed by pan I3" which discharges the completely cleaned coal at I4", and the waste at I6 The coal from the discharge means I4 descends through a chute or the like I6 onto a conveyor I1 and is carried off laterally. Another conveyor I6 is employed to convey the waste from the three outlets I6, I5, and I6, away from the machine. 7

Due to the construction and operation of the more effectively, if an abundance of the relatively heavy waste be kept upon the upper ends of said pans, near the waste outlets I6, I5, and I5". For the first pan I3, this need is fulfilled without special provision,'but I provide an adjustable gate I! in the bottom of each trough I6, for discharging some of the outgoing waste from said pan I3- onto the upper end of the pan I3. An'identical gate I9 is provided in the bottom of each trough I 5 for discharging some of the outgoing waste from said trough onto the upper end of the pan I3 Better results are attainableif the waste is only allowed to discharge periodically. I therefore provide discharge gates 20 for all of the troughs I6, I 6', and I6, and I provide means actuated by the movements of the frame I2 for actuating said gates at intervals. In the present showing, electro-magnets 2I are provided for opening the gates 20, and a rotatable switch 22 is employed for controlling the circuit of said electro-magnets. The switch 22 is provided with a ratchet wheel 23, and a pawl 24 is carried by the frame I2' to turn said ratchet wheel, thereby rotating the switch 22 at intervals and controlling the supply of current to the electro-magnets 2I- to effect gate-operation. The rotary switch may of course be such as to open the gates 20 simultaneously or in any desired sequence.

For moving the pans I3, I3, and I3 with proper impulses to jar the material thereon, to advance such materials, and to otherwise facilitate separation, I make novel provision. The frame I2 is mounted upon a plurality of spring arms 26 which incline in the opposite direction from the separating pans. The lower ends of these arms are fixedly secured at 26 to an appropriate base 21, and the upper ends of said arms are pivoted at-26 to the frame I2. When the separating pans are loaded, the spring arms 26 would normally stand downwardly sprung to some extent as indicated in Fig. 10, and the frame I2 and the separating pans thereon would then occupy a normal position. A driven cam v29, co-operable with a roller or the like 30 on the frame I2, is provided for retrogradely moving the frame I2 from this normal position (see arrow 3| of Fig. and for then releasing said frame.

-mal loaded position, as indicated by arrow 32 of Fig. 10. The recoil of the spring arms 26 then retrogradely shifts the frame I2 slightly beyond its normal loaded position, as illustrated by arrow 33 in Fig. 10, and finally restores said frame to said normal position, as shown by arrow 34 in Fig. 10. By this time, c'am 29 has rotated sulficiently to again engage the roller 30. To positively limit the first spring-effected movement of the frame l2 (see arrow 32) fixed bumper means 35 are provided, but said spring arms do not throw the frame against said bumper means with a violent blow, but on the contrary, said frame abuts said bumper means with practically no shock. When frame I2 is in its normal loaded position, it is spaced from the bumper means 35 (see Figs. 1 and 2) and said frame only engages said bumper means when it is thrown past its normal loaded position by the spring arms 25.

By operating the frame I2 in the. manner shown and described, or in an equivalent manner, I impart major material-advancing impulses separating pans I3, I3, and I3 to movement upon an arc 36 (Fig. 10) whose chord 3 'I inclines in the same general direction as said pans, said chord however, being more steeply inclined than said pans, in the present showing;

If found desirable, auxiliary spring means 36 (Fig. 1) may be operatively associated with the frame I2 to act in conjunction with the spring arms 25.

The general construction is the same for all of the pans I3, I3". and I3 and a description in connection with one will therefore sufilce. Pan I3 is best illustrated and has therefore been selected for description. The lower end of this pan is pivotally mounted on the frame I2, upon a transverse shaft 39, and the entire pan may be vertically adiusted about this pivotal mounting, by means of appropriate adjusters 40, so as to set the pan at the most'advantageous inclination, according to the materials being handled. The upper portion H of pan I3 inclines to a greater extent than the lower end portion thereof and may be vertically adjusted into different angular relations with said lower portion by adjusters 42 which may well be tum-buckles connected at their upper ends with the pan portion H and connected at their lower endswith rigid bars 43 secured to the pan bottom. This bottom is sufliciently resilient to spring when the. upper end portion of the pan is adjusted with respect to the lower portion thereof. Extensible and contractible braces 44 may well be provided to more rigidly connect the upper end portions of the pan I3 with its lower portion, as seen in Figs. 1 and 4.

The bottom of the pan I3 is provided with alternate longitudinal channels 45 and longitudinal ridges 46, said channels and ridges gradually disappearing toward the upper end of the pan and merging into a fiat bottom portion 41, which portion may well have upstanding longitudinally extending dividers 46 joined at their front ends to the front wall 49 of the pan, said gular adjustment of the upper pan portion 4| without interference. the side wall sections 52 are higher and they are joined to a lower end wall 53, giving ample depth to the pan where it receives the intermixed materials from the feeding means F.

Longitudinally extending coal outlet slots 54 are formed inthe ridges 45, between the ends of the pan l3, and the channels 45, extend somewhat beyond these outlets as shown in Fig. 3. The pan is also provided at its longitudinal edges with two additional coal discharge slots 54', and all of the slots 54 and 54 discharge into the chutes or the like M to deliver the coal and what refuse may remain therewith into the lower end of the pan [3. 4

During the operation of the machine, the relatively heavy material settles to the bottom of the bed being advanced along the pan, and the lighter -coal spills laterally from the top of the bed into the outlet slots 54-54, the channels 45 having to keep the waste away from said slots. This heavier material advances toward the spouts or the like with some of the coal still resting upon it, but the minor or short .impulse movements imparted to the pan keep this coal continually rolling back and hence discharging through the coal outlet slots. Each time the pan moves as indicated by the arrow 3|, its lower end crowds under the coal being discharged at F, and when said pan moves as indicated by the arrow 32, it throws the bed of material in the pan slightly upward and forward. The heavier particles on the bottom, due to greater weight and coeflicient of friction, tend to move forward faster than the lighter particles, and for this reason tend to move out from under the bed of lighter material. At the end of the travel indicated by arrow 32, the bed tends to pack to some extent upon the pan, but the minor impulses denoted by the arrows 33 and 34, again loosen the bed and are instrumental also in causing any coal resting upon the waste in the upper end of the pan, to roll back for eventual discharge through the outlets 54 and 54'.

A plurality of hollow agitators 55, 55 and 55 are mounted in positions for reception in the bed of materials resting on the bottom of the pan l3, said hollow agitators having perforations 55 for directing air jets into the bed of materials with insufficient force to float the lighter material being separated from the heavier, said agitators and air jets nevertheless serving to keep the bed loose to allow the desired settling of the heavier materials through the lighter. Preferably, the perforations 56 toward the bottoin of the bed are larger than those toward the top thereof, as seen in Fig. 7. These perforations may be positioned to direct the air in any directions other than upward or downward but I do not wish them directed in these two directions, because of the fact that no flotation of materials is desired, and it is not desired to have any air in appreciable quantity enter between thebed and the pan. In the preferred structure, the air jets are directed on lines substantially parallel with the bed-supporting surfaces of the pan bottom, and I prefer to provide for so adjusting the hollow agitators Toward their lower ends,

that said jets may be discharged at various angles to the direction of travel of the bed. Y

In the present disclosure, most of the agitators above described are carried by pipes 51 adjustably mounted at 53 upon transverse bars 55 which may in turn be mounted upon the brace bars 44 above described. The mountings 53 are such as to allow turning of the pipes 51 to angle the agitators'as may be desired, which will be clear from Fig. 3. Flexible tubes to connect the pipes 51 with an air main 6| leading from a blower or the like 52.

The agitators for the lower end portion of the pan, are carried by short vertical pipes 51' connected by flexible tube 60' and other pipes 63, with a lower air main 64. Suitable clamps are preferably provided for all of the flexible tubes so that they may be compressed to one extent or another, to control the pressure with which the air is supplied to the bed of materials being separated.

For manufacturing reasons and to prevent interference of any of the air conducting tubes and piping with the operation of the machine, the hollow agitators toward the lower ends of all three pans I3, l3 and I3 are supplied with air from the lower main 54, and all of the other hollow agitators of said pan l3 are also supplied from this main, but all of the other agitators may receive their air from the upper main 6|.

When the machine is being operated and a mixtureof divided materials of different specific gravities is continuously fed by the feeding means F, a bed of the materials will be constantly jarred, agitated, aerated and advanced, so that the heavier materials may descend through the lighter and discharge from the upper ends of the pans, while the lighter materials spill laterally and discharge through chutes located at ridges shown at 54 Fig. 5, having a'much shorter distance to travel than with prior machines. The relatively light materials discharging from the first pan l3, are further separated in the pan l3, and the corresponding materials discharged from the latter are given a final separation in the pan l3, all of the properly cleaned materials being carried off by the conveyor l1, and the waste by the conveyor l8.

Not only is the general construction of the machine considered of importance, but the same is true of the separating process, in which the pre-sized materials of dlfierent specific gravities are supported and agitated and in which air jets are directed into the bed of materials during agitation with insuflicient force to float the lighter pre-slzed material, yet with suflicient force to keep the bed loosened. The steps of imparting major material agitating and advancing impulses to the bed of materials at intervals, and imparting minor bed loosening impulses to said bed between said intervals, are also considered of advantage and importance. The best results are attainable when the bed loosening air jets are supplied concurrently with the application of the above-mentioned major and minor impulses.

The process involving the major and minor impulses may be further explained as follows, with little regard to apparatus. One cycle of pan operation as effected by moving the pan downwardly and rearwardly (arrow 3|, Fig. 10) then imparting a long rapid forward and upward stroke to said pan (arrow 32) then imparting a shorter and slower rearward and downward stroke to said pan (arrow 33), and finally imparting a still shorter and still slower forward and upward stroke to said pan (arrow 34). The second cycle which is a duplicate of the first is started only when the final "still shorter and still slower" stroke of the first cycle has been completed. Pan operation is continued by duplicating the aforesaid cycles and maintainingthe same relation between the successive cycles, as that existing between said-first and second cycles, that is, no cycle is started until the final "still shorter and still slower" stroke of the preceding cycle has been completed. The long rapid strokes (arrow 32) throw and advance the bedoi material on the pan, and the shorter and slower (arrow 33) and the still shorter and still slower strokes (arrow 34) loosen the bed to facilitate settling of the heavier material through the lighter. When the herein disclosed machine or a similar machine is used for carrying out the process, the pan load must necessarily be restricted to such weight as to insure proper functioning of the vibratoryresillent means 25 or the like. Either too much weight or too little weight will result in loss of synchronism between the pan and the cam 29 or the like, and the machine will not successfully operate.

A dust hood 66 having curtains 66' is preferably used over the machine, and a suction pipe 61 and fan 68 are employed to draw dust from said hood and discharge it into a dust separator 69.

On account of the excellent results flowing from the general construction herein disclosed, it is preferably followed but attention is again invited to the possibility of making numerous variations within the scope of the invention as claimed.

One or more pans can be mounted on frame l2,

preferably three pans.

Most of the heavier gravity material is settled to the bottom on pan l3, approximately particles with gravity +1.70. I

t On pan [3* particles with gravity of betwee 1.70 and 1.60 approximately settle to the bottom.

On pan l3 waste particles of a gravity lighter than 1.60 settle to the bottom.

Clamps 65 are necessary in order to get a uniform air velocity in relation to the thickness of the bed of material.

In practice it is found that approximately 8 is a satisfactory elevation, the degree of elevation differing for difierent materials.

I claim:

1. In a machine for separating intermixed divided materials of difierent specific gravities, a pan for advancing and separating the materials,

and repeatedly acting driven means for moving said pan retrogradely away from its normal loaded position, for then quickly advancing said pan slightly past said normal position, for then quickly moving said pan retrogradely slightly beyond said normal position, and for then restoring said pan to said normal position, whereby to alternately advance and loosen the bed of materials.

2. In a machine for separating intermixed divided materials of different specific gravities, a pan for advancing and separating the materials, means for moving said pan retrogradely from its normal loaded position and for then releasing said pan, spring means energized bysaid retrograde pan movement for quickly advancing said pan slightly past said normal position, for then retrogradely moving said pan slightly beyond said normal position, and for then returning said pan to said normal position, and means for actuating the first named means after each return of said pan to said normal position, whereby to alternately advance and loosen the bed of materials. 3. A structure as specified in claim 1; including means for confining said pan to movement upon an arc whose chord inclines in the direction in which the materials are to be advanced.

4. A structure as specifiedin claim 2; including means for confining said pan to movement upon an arc whose chord inclines in the direction in which the materials are to be advanced.

5. A structure as specified in claim 2; said spring means consisting of spring arms, operatively connected with and supporting said pan, said spring arms being fixedly secured at one end and being inclined to confine said pan to movement on an arc whose chord inclinesin the direction in which the materials are to be advanced.

6. In a machine for separating intermixed divided materials of different specific gravities, an inclined pan having a heavy material outlet at its upper end and a lateral light material outlet, means for continuously feeding the intermixed materials into the lower end of said pan, repeatedly acting driven means for moving said pan retrogradely from its normal loaded position, for then quickly advancing said pan slightly past said normal position, for then quickly moving said pan retrogradely slightly beyond said normal position, and for then restoring said pan to said normal position, and means for confining said pan to movement on an arc whose chord inclines in the same general direction as said pan. whereby to alternately advance and loosen the bed of intermixed materials.

7. In a machine for separating intermixed divided materials of different specific gravities, an inclined pan having a heavy material outlet at its upper end and a lateral light material outlet, means for continuously feeding the intermixed materials into the lower end of 'said pan, means for confining said pan to movement on an arc whose chord is inclined in the same general direction as said pan, means for moving said pan retrogradely from its normal loaded position and for then releasing said pan, spring means energized by said retrograde pan movement for quickly advancing said pan slightly past said normal position, for then retrogradely moving said pan slightly beyond said normal position, and for then returning said pan to said normal position, and means for actuating the first named means after each return of said pan to said normal position, whereby to alternately advance and loosen the bed of intermixed materials.

8. A structure as specified in claim 7; said spring means and said means for confining said pan to arcuate movement, consisting of spring arms fixedly anchored at one end and operatively connected with said pan.

9. In a machine for separating pre-sized intermixed divided materials, impertorate means for supporting a bed oi! the intermixed materials, means for moving said supporting means to advance the bed, and vertical splitting means for the advancing bed having means for directing bed-loosening jets of air into said bed on lines substantially parallel with the bed-supporting surface of said supporting means, said bed-splitting means having means for directing stronger jets into the lower portion of the bedthan into the upper portion of said bed, all oil the Jets being discharged with force insufiflcient to float the lighter gravity material to be separated from the heavier.

10. In a machine for separating pre-sized intermixed divided materials, imperiorate means for supporting a bed of the intermixed materials,

bed-splitting means having means for directing stronger jets into the lower portion of the bed than into the upper portion of said bed, all of the jets being discharged with force insuflicient to float the lighter gravity material to be separated from the heavier.

11. In a machine for separating intermixed di-- vided materials, means for supporting and advancing a bed of intermixed materials, hollow agitators mounted in position for reception in the advancing bed of intermixed materials, said agitators having perforations for directing jets of air into said bed to loosen the bed and allow the heavier materials to descend through the lighter, and means for discharging air under pressure into said hollow agitators, some of said perforations being toward the bottom of the bed and of relatively large diameter, and some of said perfora tions being toward the top of the bed and of comparatively small diameter.

12..In a machine for separating intermixed divided materials, means for supporting a bed of the intermixed materials, hollow agitators in position for reception in the advancing bed of intermixed materials, said agitators having perforations for directing jets of air into said bed to loosen the same and allow settling of the heavier materials through the lighter, means for discharging air under pressure into said hollow agitators, and means for adjustably mounting said hollow agitators to allow varying of the directions of discharge of said jets, some of said perforations being toward the bottom of the bed and of relatively large diameter, and some of said perforations being toward the top of the bed and oi comparatively small diameter.

13. A structure as specified in claim 6; together with hollow vertical bed-splitting agitators mounted in position for reception in the advancing bed of materials on said pan, said agitators having perforations for discharging bed-loosening jets of air into said bed, means for discharging air under pressure into said hollow agitators, and means mounting said agitators for movement unitarily with said pan.

14. In a machine for separating intermixed divided materials of difierent specific gravities, an inclined pan provided with parallel longitudinal edges and with an imperforate bottom, said pan having an outlet at its upper end for the heavier material, said pan having a lateral outlet between its ends for the lighter material, means for feeding the intermixed materials into the lower end of said pan, means for imparting material-advancing impulses to said pan, and hollow vertical bed-splitting agitators over the imperforate pan bottom and having lateral perforations for directing jets of air into the advancing bed of material to continuously loosen the bed, said jets being sufliciently weak to prevent them from floating the lighter material, the

cross section of said pan bottom being varied from channel form at its lower receiving end to fiat channels, said ridges and channels all merging into a flat bottom portion at the delivery and of the pan, means for feeding the intermixed materials into the ends of the channels remote from said iiat bottom portion, the other end of said pan having outlet means for the heavier material-located at the end of said flat bottom portion, means for imparting impulses to said pan to advance the bed of intermixed materials, and outlets ior the lighter material located in said ridges between the ends of the pan and at the longitudinal edges of said pan.

16. In a machine for separating intermixed divided materials of diflerent specific gravities, a pan having an imperforate bottom provided with alternate longitudinal ridges and longitudinal channels, said ridges and channels all merging into a flat bottom portion at the delivery end of the pan, means for feeding the intermixed materials into the ends of the channels remote from said flat bottom portion, the other end of said pan having outlet means for the heavier material located at the end of said flat bottom portion, outlets for the lighter materials located in said ridges between the ends of said pan and at the longitudinal edges of said pan, means for movably mounting said pan in a position inclined away from said material feeding means and tor confining said pan to movement on an arc whose chord inclines in the same general direction as said pan, and means for imparting major material-advancing impulses to said pan at intervals, and for imparting minor material-loosening impulses to said pan between said intervals.

17. In a machine for separating intermixed divided materials of diflerent specific gravities, a pan having an imperforate bottom provided with alternate longitudinal ridges and longitudinal channels, said ridges and channels merging into a fiat bottom portion at the delivery end of the pan, means for feeding the intermixed materials into the ends oi the channels remote from said flat bottom portion, the other end of said pan having outlet means for the heavier material disposed at the end of said fiat bottom portion, outlets for the lighter materials located in said ridges between the ends of said pan and at the longitudinal edges of said pan, means for movably mounting said pan in a position inclined away from said material feeding means and for confining said pan to movement on an arc whose chord inclines in the same general direction as said pan, means for moving said pan retrogradely from its normal loaded position and for thenreleasing said pan, spring means energized by said retrograde pan movement for quickly advancing said pan slightly past said normal position, for then retrogradely moving said pan slightly beyond said normal position, and for then returning said pan to said normal position, and means for actuating the first named pan-moving means after each return of said pan to said normal position.

18. A structure as specified in claim 16; together with hollow agitators mounted for reception in the advancing bed of material, said agitators having perforations for directing bedloosening jets of air into the advancing bed of material, and means for supplying air under pressure to said hollow agitators.

19. In a machine for separating intermixed divided materials of difierent specific gravities, means for separating relatively light materials from relatively heavy material and advancing them toward outlets, additional separating means for further separating and advancing the relatively light materials discharged from the first named means according to their specific gravities, and means for directing some of the heavy material discharged from said first named means onto the stratified heavy material near the heavy material outlet of said additional means.

20. In a machine for separating intermixed divided materials of different specific gravities, a movably mounted frame, at least two superposed pans fixedly mounted on said frame, said pans being inclined substantially unidirectionally and being in overlapped relation, means for feeding intermixed materials onto the lower end of the upper pan, said upper pan having an outlet between lts ends for discharging relatively light materials onto the lower end of the other pan, said other pan being provided also with an outlet between its ends for relatively light material, both pans having outlets at their upper ends for the heavier material, and means for imparting material-advancing impulses to said frame, together with means for directing someof the heavy material discharged by said upper pan onto the advancing stratified heavy material near the heavy material outlet at the upper end of the other pan.

21. In a machine for separating intermixed divided materials of different specific gravities, a reciprocatory pan upon which the materials are separated, said pan having outlets for the relatively light and heavy materials, a gate for the heavy material outlet, electro-magnetic means for periodically operating said gate, a rotatable switch member for energizing said electromagnetic means, and ratchet means actuated by the pan reciprocation for rotating said switch member.

22. In a machine for separating intermixed divided materials, means for supporting a bed of said intermixed materials, means for moving said supporting means to advance the bed, a plurality of hollow agitators mounted over said bed-supporting means in position to split through the bed, said agitators each having side, top, bottom and end walls, said side walls having perforations for directing substantially horizontal air jets into the bed, and means for conducting air under pressure into said hollow agitators, some of said perforations being toward the bottom of the bed and of relatively large diameter, and some of said perforations being toward the top of the bed and of comparatively small diameter.

23. In a machine for separating intermixed divided materials, means for supporting a bed of said intermixed materials, means for moving said supporting means to advance the bed, a plurality of hollow agitators mounted over said bed-supporting means in position to split through the bed, said agitators each having side, top, bottom and endlwalls, said side walls having perforations for directing substantially horizontal air jets into the bed, and means for conducting air under pressure into said hollow agitators, said agitators being mounted on vertical axes for turning into oblique relation with the bed.

24. In a machine for separating intermixed divided materials, means for supporting a bed of said intermixed materials, means for moving said supporting means to advance the bed, a plurality of hollow agitators mounted over said bed-supporting means in position to split through the bed, said agitators each having side, top, bottom and end walls, said side walls having perforations for directing substantially horizontal air jets into the bed, and means for conducting air under pressure into said hollow agitators, said agitators being disposed in parallelrows extending longitudinally of said supporting. means ;and being mounted on vertical axes for turning intooblique relation with the bed.

25. A process of separating intermixed divided materials with the aid of a pan; consisting in efi'ecting one cycle of pan operation by moving the pan downwardly and rearwardly, then imparting a long rapid forward and upward stroke to said pan, then imparting a shorter and slower rearward and downward stroke to said pan, and finally imparting a still shorter and still slower forward and upward stroke to said pan; effecting a second and duplicate cycle of pan operation only when said final still shorter and stillslower stroke of the first cycle has been completed; and continuing pan operation by duplicating the aforesaid cycles and maintaining the same relation between the successive cycles as that existing between said first and second cycles; whereby the long rapid strokes will throw and advance the bed on the panand the shorter and slower and the still shorter and still slower strokes will loosen the bed to facilitate settling of the heavier material through the lighter.

26. A process of separating intermixed divided materials with the aid of a separating pan and resilient means capable of vibrating and reciprocating the pan with one long rapid forward and upward stroke, one shorter and slower rearward and downward stroke and one still shorter and still slower forward and upward stroke; consisting in confining the pan load to such weight that said resilient means may function in the above stated manner; effecting the first cycle of pan operation by moving said pan rearwardly and downwardly to tension said resilient means, and then releasing said pan to allow said resilient means to impart said long rapid forward and upward stroke, said shorter and slower rearward and downward stroke and said still shorter and still slower forward and upward stroke to the pan; effecting a second and duplicate cycle of pan operation only when said still shorter and still slower forward and. upward stroke of the first cycle has been completed; and continuing pan operation by duplicating the aforesaid cycles and maintaining the same relation between the successive cycles as that existing between said first and second cycles; whereby the long strokes will throw and advance the bed on the pan and the shorter and still shorter strokes will loosen the bed to facilitate settling of the heavier material through the lighter.

27. In a machine for separating intermixed divided materials of difierent specific gravities, a pan for forwardly feeding and separating the materials, and operating means for said pan comprising a cam for moving said pan downwardly and rearwardly from its normal loaded position and then releasing said pan, spring means energized by said downward and rearward pan movement for quickly moving said pan upwardly and forwardly slightly past said normal position, for then moving said pan downwardly and rearwardly slightly beyond said normal position, and for then moving said pan upwardly and forwardly to said normal position, and means for actuating said cam to again move said pan downwardly and rearwardly after each return thereof to said normal position.

v KENNETH DAVIS. 

